1. Field of the Invention
The present invention relates to a chip scale gas discharge protective device and fabrication method of the same, and more particularly, to a chip scale gas discharge protective device whose metal coupled electrodes are fabricated through processes of yellow light image formation and metal electrode electro-casting, and the two electrodes facing each other in arch lines with the distance of a gap controlled within the range of 0.5˜10 μm, wherein the entire structure is performed by a bridge process without an extra gas filling procedure in the gap. Due to the fact that the gap between the two electrodes is as small as only several μm, a relevant potential difference existing across there is sufficient to ionize the air thereby suppressing the value of voltage of electro-static discharge (ESD) through the protected electronic device.
2. Description of the Prior Art
The over-voltage protection or the discharge protection device is absolutely necessary for telephones, facsimile machines, data phones, etc. For the aforementioned electro communication equipments, it is of a great importance to protect them from damage due to an attack of abnormal electro-static discharge (ESD).
There are a lot of prevention designs for ESD; for example, provision of electric shielding, discharge gap, capacitor, laminated MLV, semiconductor device, etc.
Among them, the provision of a discharge gap is the most popular for over-voltage protection, especially the dielectric substance used to fill between the two electrodes for the discharge gap plays the most important role in the over-voltage protection, and gaseous substances presently in use are generally considered to be quite satisfactory.
Taking air to be filled between two copper electrodes (e.g. air used as the dielectric medium for the discharge gap) for instance, when the device is undergoing ESD, the relation between the distance of the electrodes and the discharge initiation voltage is shown in FIG. 4.
However, in an air discharge device conventionally in use, its gap is normally made of the diamond cutting or laser trimming process so as to form a discharge gap with a distance of about 10˜30 μm between two electrodes, thereby keeping a rather high initiation energy of discharge. Thus, the air discharge device constructed as such is merely applicable to lightning or high energy surge impulse protection. As for ESD protection for the precision electronic communication equipment, a further consideration is required.